JP2012125670A - Polycrystalline silicon crushing device and method for manufacturing polycrystalline silicon crushed matter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device suitable for crushing polycrystalline silicon capable of crushing the polycrystalline silicon into masses with a desired size for managing the maximum target dimension, and a method for manufacturing the polycrystalline silicon using the crushing device.SOLUTION: The polycrystalline silicon crushing device 1 holds massive polycrystalline silicon between a pair of main rolls 3 reversely rotating to each other around parallel axes to crush the silicon. A sub roll 4 (receiving member) for receiving the polycrystalline silicon passing a gap G1 is provided below the gap G1 of the two main rolls 3. Each facing gap G2 between the sub roll 4 and the main rolls 3 is set to be equal to or smaller than the gap G1.

Description

  The present invention relates to an apparatus for crushing polycrystalline silicon as a raw material such as silicon for semiconductors into a lump and a method for producing polycrystalline silicon crushed material using the crushing apparatus.

A silicon wafer used for a semiconductor chip is manufactured from, for example, single crystal silicon manufactured by the Czochralski (CZ) method. For the production of single crystal silicon by the CZ method, for example, a material obtained by crushing polycrystalline silicon formed into a rod shape by the Siemens method into a lump shape is used.
As shown in FIG. 11, the polycrystalline silicon is crushed by making the polycrystalline silicon rod R into a mass C having a size of several millimeters to several centimeters. The rod R is appropriately sized by thermal shock or the like. A method of directly crushing with a hammer after crushing is generally used, but the burden on the operator is large, and it is inefficient to obtain a lump of a desired size from rod-shaped polycrystalline silicon.

  Patent Document 1 discloses a method of obtaining massive silicon by crushing rod-shaped polycrystalline silicon with a roll crusher. This roll crusher is a single roll crusher in which one roll is accommodated in a housing, and a plurality of teeth are formed on the roll surface, and polycrystalline silicon is sandwiched between gaps between these teeth and the inner wall surface of the housing. The rod-shaped polycrystalline silicon is crushed by applying a continuous impact.

  On the other hand, Patent Document 2 and Patent Document 3 propose a crushing apparatus that crushes coarsely crushed massive polycrystalline silicon. These apparatuses are double roll crushers that include two rolls and crush the bulk polycrystalline silicon between the rolls.

  By the way, in this kind of roll crusher, the gap between the roll and the inner wall surface of the housing in Patent Document 1 and the gap between both rolls in Patent Document 2 and Patent Document 3 are set as the maximum target dimensions of the crushed material to be obtained. Is done. However, the polycrystalline silicon to be input is not necessarily a fixed shape, and there is a shape elongated in a specific direction. When such polycrystalline silicon is introduced along the length direction of the roll, it may pass through the gap described above, and polycrystalline silicon larger than the maximum target dimension determined by the gap is mixed into the target crushed material. There is a risk.

JP 2006-122902 A Special table 2009-53172 JP 2006-192423 A

  The present invention has been made in view of such circumstances, an apparatus suitable for crushing polycrystalline silicon, which can crush polycrystalline silicon into a lump of a desired size and manage the maximum target dimension, and the apparatus. It aims at providing the manufacturing method of the polycrystalline silicon crushed material using the crushing apparatus.

  A polycrystalline silicon crushing apparatus according to the present invention is a polycrystalline silicon crushing apparatus that crushes by crushing massive polycrystalline silicon between a pair of rolls rotating in opposite directions around a parallel axis. A receiving member that receives the polycrystalline silicon passing through the gap is provided below, and a facing interval between the receiving member and each roll is set to be equal to or smaller than the gap. .

Even if elongated polycrystalline silicon having a length larger than the gap between the rolls is not crushed in the roll gap and passes through the gap, it is received by the receiving member below the roll, and is attached to either the left or right side of the receiving member. It falls and can be crushed between the opposing space | intervals of a receiving member and each roll at that time.
In this case, the maximum target dimension of the obtained polycrystalline silicon may be set according to the facing distance between the receiving member and each roll.

In the polycrystalline silicon crushing device according to the present invention, the receiving member is formed in an arcuate surface centered on an axis parallel to the axis of the roll, and can be rotated about the axis. It is good to be.
If the facing portion of the receiving member facing the roll is formed on an arc surface and is rotatable, the polycrystalline silicon is crushed without being crushed, and generation of fine powder can be prevented.

  In the polycrystalline silicon crushing apparatus according to the present invention, a plurality of crushing teeth protrude radially outward on the outer peripheral surface of the roll, and each crushing tooth has a tip surface formed in a spherical shape. In addition, the side surface may be formed in a conical surface shape or a cylindrical surface shape.

  In this crushing apparatus, polycrystalline silicon can be continuously hit by crushing teeth while rotating the roll, and can be efficiently crushed. In addition, since the tip surface of the crushing tooth is formed in a spherical shape, the tip of the crushing tooth and the polycrystalline silicon are in a point contact state, and the side surface of the crushing tooth is also formed in a conical or cylindrical shape. Therefore, when the side surface of the crushing tooth comes into contact with the polycrystalline silicon, it is in a line contact state. Therefore, since the crushing teeth and the polycrystalline silicon are in a point contact or line contact state, it is prevented that the polycrystalline silicon is crushed by the crushing teeth and fine powder is generated.

  The method for producing a crushed polycrystalline silicon according to the present invention is characterized by producing a crushed polycrystalline silicon using any one of the crushing apparatuses.

  According to the present invention, since the polycrystalline silicon can be continuously and efficiently crushed by the rotation of the roll, and the receiving member is provided below the gap of the roll, the elongated polycrystalline silicon passes through the gap of the roll. There is no possibility of falling and mixing of crushed material exceeding the maximum target dimension can be prevented with high probability.

It is a front view which shows one Embodiment of the crushing apparatus of the polycrystalline silicon which concerns on this invention. It is a perspective view of the main roll in the crushing apparatus of FIG. It is a perspective view of the main roll surface of FIG. It is the perspective view seen from the back of the crushing tooth unit attached to the crushing device. It is a perspective view of the crushing tooth unit in the state where two or more were arranged. It is a perspective view of a crushing tooth. It is a front view explaining the positional relationship in the opposing part of a main roll. It is a front view explaining the positional relationship in the opposing part of a main roll and a sub roll. (A) explaining a pyramid-shaped crushing tooth is a perspective view, (b) is a front view in the opposing part of a roll. It is a perspective view which shows two types of modifications of (a) and (b) about a crushing tooth. It is a schematic diagram which shows what crushed the rod of polycrystalline silicon into a lump.

Hereinafter, embodiments of a polycrystalline silicon crushing apparatus and a method for producing a polycrystalline silicon crushed material using the crushing apparatus according to the present invention will be described with reference to the drawings.
In the crushing apparatus 1 of the present embodiment, as shown in FIG. 1, two main rolls 3 are arranged in a housing (not shown) in parallel with their rotational axes directed in the horizontal direction. 3, a sub roll 4 (receiving member) having an axis parallel to the rotation axis of the main roll 3 is provided below the gap G <b> 1. As shown in FIGS. 1 and 2, the rolls 3 and 4 have a plurality of crushing teeth 5 projecting radially outward from the outer peripheral surface. In this case, as shown in FIG. 3, the outer peripheral surfaces of the rolls 3 and 4 are not uniform circular arc surfaces, but a polyhedral shape formed by connecting long flat surfaces 6 along the axial direction in the circumferential direction. The screw holes 7 are provided at both ends of each flat surface 6, and the crushing tooth units 8 shown in FIG. 4 are fixed to the flat surfaces 6 one by one.

  Moreover, although the main roll 3 and the sub roll 4 have the same shape and size of the crushing tooth units 8, the two main rolls 3 are formed to have the same diameter, and the same number of crushing tooth units 8 are attached. On the other hand, the sub-roll 4 is formed to have a smaller diameter than the main roll 3, and the number of the crushing tooth units 8 to be attached is reduced accordingly. The main roll 3 is rotationally driven in opposite directions by a rotation mechanism (not shown), but the sub roll 4 is supported in a rotatable state.

As shown in FIGS. 4 and 5, the crushing tooth unit 8 includes a strip-shaped fixed cover 11 that comes into contact with the flat surface 6 of the rolls 3 and 4, and a plurality of crushing teeth 5 attached to the fixed cover 11. It is configured.
As shown in FIG. 6, the crushing teeth 5 are made of a cemented carbide or a silicon material, and as shown in FIG. 6, the columnar portion 13 and the flange portion 14 having a slightly thickened diameter at its proximal end portion are integrally formed. ing. The columnar portion 13 has a tip surface 15 formed in a spherical shape and a side surface 16 formed in a cylindrical surface shape. The collar portion 14 has a shape in which both side portions of the circular plate are cut out in parallel with the longitudinal direction of the columnar portion 13, and the flat portion 17 is formed in an opposite direction by 180 ° by the cut out portion.

  The fixed cover 11 is formed in a strip shape having the same width and length as the flat surface 6 of the rolls 3 and 4, and crushing tooth fixing holes 21 are formed in a penetrating state at intervals in the longitudinal direction. A screw insertion hole 22 is formed in the portion. As shown in FIG. 4, the crushing teeth fixing holes 21 are formed into fitting holes 23 having a circular cross section corresponding to the side surfaces 16 of the columnar portions 13 of the crushing teeth 5 up to half of the thickness of the fixing cover 11. One half is an enlarged diameter portion 25 having a flat portion 24 corresponding to the collar portion 14 of the crushing tooth 5. In the crushing teeth 5, the collar portion 14 is fitted to the enlarged diameter portion 25 with the columnar portion 13 fitted in the fitting hole 23 of the fixed cover 11, and the flat portion 24 and the collar portion 14 of the fixed cover 11 are fitted. By contacting the flat portion 17, the flat portion 17 is held in a state of being prevented from rotating by the fixed cover 11.

In this case, the fixed cover 11 has each of the flat surfaces 6 of the rolls 3 and 4 in a state in which the diameter-increased portion 25 faces the surfaces of the rolls 3 and 4 and the columnar portions 13 of the crushing teeth 5 protrude from the fitting holes 23. And both ends thereof are fixed to the roll surface by screws 26.
Further, each crushing tooth unit 8 has a staggered shape as shown in FIG. 5 so that crushing teeth 5 of adjacent crushing tooth units 8 do not line up continuously in the circumferential direction of rolls 3 and 4. Installed in an array. On the other hand, between the two main rolls 3, as shown in FIG. 7, it arrange | positions so that the front end surfaces 15 of the crushing tooth | gear 5 of the main roll 3 may oppose in the opposing part. In FIG. 7, among the crushing teeth 5 arranged in a staggered manner, one row of crushing teeth 5 arranged on the same circumference is shown by a solid line, and the crushing teeth 5 of the other row are shown by two-dot chain lines. Is shown.

And in this embodiment, as the size (maximum target dimension) of the lump of polycrystalline silicon after crushing (polycrystalline silicon crushed material), the maximum side length of 5 to 60 mm is obtained, In order to obtain a lump of that size, each crushing tooth 5 has a columnar portion 13 with a diameter D of 10 to 14 mm, and a protruding height H from the surface of the fixed cover 11 shown in FIG. The distance L1 between the adjacent crushing teeth 5 on the main roll 3 is set to 11 to 35 mm. Moreover, in the opposing part of the two main rolls 3, the opposing gap G1 between the tip surfaces 15 of the crushing teeth 5 is set to 5 to 30 mm.
On the other hand, in the secondary roll 4, as shown in FIG. 8, the interval L2 between adjacent crushing teeth is 11 to 35 mm, and the opposing gap G2 between the front end surfaces of the crushing teeth between the main roll 3 is 3 to 20. It is set to be the same as or smaller than the gap G1 between the two main rolls 3.

In the case of producing a crushed polycrystalline silicon using the crushing apparatus 1 configured as described above, an appropriate size of polycrystalline silicon that has been roughly crushed in advance between the main rolls 3 in a state where the two main rolls 3 are rotated. The polycrystalline silicon is further crushed between the crushing teeth 5 of the two main rolls 3 and subdivided into lumps.
At this time, even if the elongated polycrystalline silicon having a length larger than the gap G1 between the main rolls 3 passes between the two main rolls 3, it is received by the sub roll 4 below the gap G1 between the main rolls 3. Can do. Then, the polycrystalline silicon falls on either the left or right side of the sub roll 4 and is crushed between the opposing gaps G <b> 2 between the sub roll 4 and the main roll 3.
As described above, since the polycrystalline silicon can be continuously hit by the crushing teeth 5 while rotating the main roll 3 and can be efficiently crushed, the polycrystalline silicon is crushed to a size less than the maximum target dimension. be able to.

Since each of the crushing teeth 5 has a tip surface 15 formed in a spherical shape, the tip surface 15 and the polycrystalline silicon are in point contact, and the side surface 16 of the columnar portion 13 is formed in a cylindrical surface shape. Therefore, the side surface 16 and the polycrystalline silicon are in point contact or line contact. For this reason, since the crushing teeth 5 apply an impact to the polycrystalline silicon in a point contact or line contact state, crushing the polycrystalline silicon on the surface is reduced.
Further, since the sub roll 4 is formed in a circular arc shape centering on an axis parallel to the rotation axis of the main roll 3 and is supported so as to be rotatable about the axis, the polycrystalline silicon is made of It is crushed without being crushed, and generation of fine powder can be prevented.

Incidentally, as shown in FIG. 9A, when the crushing teeth 35 are formed in a pyramid shape, as shown in FIG. 9B, there are many gaps between the crushing teeth 35 facing each other as shown in FIG. Crystalline silicon may be sandwiched and crushed between the flat surfaces 35a of the crushing teeth 35, and this will be in surface contact, resulting in fine powder. In the example shown in FIG. 9, since the front end surface 35b of the crushing tooth 35 is also formed as a flat surface, it is also crushed by this front end surface 35b.
Although it is difficult to prevent the generation of fine powder with a crushing tooth having such a flat surface, the crushing tooth of the present embodiment has a spherical shape at the tip of the columnar part and a side surface formed in a cylindrical shape. The generation of fine powder can be reduced.

  Moreover, in this crushing apparatus 1, since the crushing tooth | gear 5 is formed with the cemented carbide or the silicon material, it is prevented that an impurity mixes into a polycrystalline silicon from this crushing tooth | gear 5. FIG. On the other hand, the screw 26 for fixing the crushing tooth unit 8 is generally made of metal, but this screw 26 is arranged outside the polycrystalline silicon crushing space 33 by the partition plate 31, so that polycrystalline silicon is used. The housing 2 is also made of a resin such as polypropylene or is coated with tetrafluoroethylene, so that impurities are prevented from being mixed into the polycrystalline silicon being crushed. Therefore, according to this crushing apparatus 1, a high quality thing can be obtained as a polycrystalline silicon for semiconductor raw materials.

  Furthermore, in this embodiment, each crushing tooth 5 is held by the fixed cover 11 to constitute a crushing tooth unit 8, and this crushing tooth unit 8 is fixed to the surface of the roll 3. Even if a defect or the like occurs in the tooth 5, it is only necessary to replace the crushing tooth 5 in which the defect is generated. In that case, the crushing tooth unit 8 is fixed to the roll 3 by screwing, and the crushing tooth 5 is It only fits into the crushing tooth fixing hole 21 of the fixed cover 11, and its replacement work is also easy. The fixed cover 11 is preferably made of stainless steel or the like for securing the strength. However, if the surface is coated with a resin such as polypropylene or tetrafluoroethylene, contamination is prevented even when it comes in contact with polycrystalline silicon. Can be prevented.

FIG. 10 shows a modified example of the crushing teeth used in the crushing device 1. Each crushing tooth 41, 42 has the columnar part 43 and the collar part 24 in the same manner as the crushing tooth 5 of one embodiment, and the shape of the collar part 24 is the same as that shown in FIG. In these drawings, common parts are denoted by the same reference numerals.
In the crushing tooth 41 shown in FIG. 10A, the side surfaces 44a and 44b of the columnar portion 43 are formed in a cylindrical surface shape from the collar portion 24 to the middle position in the longitudinal direction, but the tip portion is conical than the middle position. The tip surface 45 is formed in a spherical shape. In this case, the cylindrical surface 44a is formed to be half or less of the length of the columnar portion 43, and the conical surface 44b is longer than the cylindrical surface 44a.
Further, the crushing teeth 42 shown in FIG. 10B are formed such that the cylindrical surface side surface 44a of the columnar part 43 is longer than the crushing teeth 41 shown in FIG. 10A, and more than half the length of the columnar part 43. The length of the conical surface 44b is shortened accordingly.

In addition, this invention is not limited to the said embodiment, A various change can be added in the range which does not deviate from the meaning of this invention.
For example, in the said embodiment, although arrange | positioned so that the front end surface of a crushing tooth might oppose in the opposing part of both rolls, so that the crushing tooth of one roll may oppose between the crushing teeth which the other roll adjoins. You may arrange.
Moreover, various dimensions, such as the opposing space | interval of the crushing tooth demonstrated by one Embodiment, are not necessarily limited to this.

DESCRIPTION OF SYMBOLS 1 Crushing device 3 Main roll 4 Sub roll 5 Crushing tooth 6 Flat surface 7 Screw hole 8 Crushing tooth unit 11 Fixed cover 13 Column-shaped part 14 Collar part 15 Tip surface 16 Side surface 17 Flat part 21 Crushing tooth fixed hole 22 Screw insertion hole 23 Fit Joint hole 24 Planar portion 25 Expanded portion 26 Screw 41, 42 Crushing teeth 43 Columnar portion 44a Columnar side surface 44b Conical side surface 45 Tip surface

Claims (4)

  A polycrystalline silicon crushing apparatus for crushing a bulk polycrystalline silicon sandwiched between a pair of rolls rotating in opposite directions around a parallel axis, the polycrystalline silicon passing under the gap between both rolls The polycrystalline silicon crushing apparatus is characterized in that a receiving member is provided, and a facing gap between the receiving member and each roll is set to be equal to or smaller than the gap.   The said receiving member is formed in the circular arc surface shape centering on the axis | shaft parallel to the axial center of a roll, and the opposing part with each roll is rotatable centering | focusing on the said axis | shaft. Polycrystalline silicon crusher.   A plurality of crushing teeth protrude radially outward on the outer peripheral surface of the roll, and each crushing tooth has a tip surface that is formed into a spherical shape and a side surface that is conical or cylindrical. The polycrystalline silicon crushing apparatus according to claim 1, wherein the polycrystalline silicon crushing apparatus is formed. A method for producing a crushed polycrystalline silicon product, comprising producing a crushed polycrystalline silicon product using the polycrystalline silicon crushing device according to claim 1.

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